Prosthetic attachment locking devices are used to secure a patient's residual limb, which is fitted in a prosthetic socket, to a pylon of a prosthetic limb. The prosthetic attachment locking device typically includes a body having an axial hole extending therethrough and a releasing mechanism having a spring loaded reciprocating pawl that cooperates with the axial hole. The prosthetic socket is attached to a first surface of the body by fasteners such as screws that are received through a plurality of through-holes. A ratcheted attachment pin that extends from a distal end of a liner positioned on the patient's residual limb is inserted through the prosthetic socket and through the axial hole of the prosthetic attachment locking device until a distal end of the attachment pin is received in the pylon of the prosthetic limb. The attachment pin is secured in the prosthetic attachment locking device by the pawl that engages the teeth of the attachment pin. The pawl rotates in only one direction, so that the attachment pin may be inserted into the axial hole, but not removed therefrom. To release the attachment pin from the prosthetic attachment locking device, the release mechanism displaces the pawl from the axial hole so that the patient can pull-out the attachment pin and remove the residual limb from the prosthetic limb.
In these devices, it is preferable that the release mechanism projects from the body of the prosthetic attachment locking device toward the interior of the residual limb for comfort and accessibility. Because the pawl only rotates in one direction, a prosthetic attachment locking device that has a releasing mechanism projecting toward the interior of a left-side residual limb is incapable of being used on a right-side residual limb in a way that enables the releasing mechanism to project toward the interior of the right-side residual limb. Similarly, a prosthetic attachment locking device that has a releasing mechanism projecting toward the interior of a right-side residual limb is incapable of being used on a left-side residual limb in a way that enables the releasing mechanism to project toward the interior of the left-side residual limb. It is therefore necessary to manufacture prosthetic attachment locking devices having different designs to accommodate either a right-side residual limb or a left-side residual limb.
In these devices, it is also preferable that the release mechanism, especially the pawl, is prevented from moving with respect to the attachment pin in order to prevent the attachment pin from loosening from its attached state in the prosthetic attachment locking device. Because many prosthetic attachment locking devices do not contain locking means for the releasing mechanism or are merely threaded into the body, the fastening mechanism becomes loose and resultantly weakens the attachment of the attachment pin to the prosthetic attachment locking device. Further, many prosthetic attachment locking devices merely use through-holes and an attachment means such as screws to fasten the body to the prosthetic socket. Because the attachment surface of the prosthetic socket is grinded during manufacturing, the socket surface is often irregular. The through-holes in the body are not manufactured to evenly distribute torque caused by the irregular socket surface causing the prosthetic socket to become uneven and uncomfortable to the patient.
It is therefore desirable to develop a prosthetic attachment locking device that is reversible in that the releasing mechanism will project toward the interior of the residual limb whether used on a right-side residual limb or a left-side residual limb enabling versatility and decreasing manufacturing costs. It is also desirable to provide a prosthetic attachment locking device whereby the releasing mechanism is maintained in an attached state, and the prosthetic socket evenly distributes torque to increase patient comfort.